The date and origin of a rare piece of micro mosaic, of extraordinary beauty and technical quality, displayed in the Medieval Museum of Bologna after its restoration in 1995 and labeled as Art of Constantinople, 11th-12th centuries are here reexamined. The mosaic restorer G. Cucco, documents the technical details of the mosaic and its status of conservation before the intervention, in comparison with a wide range of mosaic works from Italy and abroad. Magdelena Stoyanova assess the results of the historic, iconographic, stylistic, technic and technological investigations in their interrelated complexity, in order to establish more precisely the probable origin and date of the work. The opinions of both the authors categorically reject the attribution of this panel in the Byzantine epoch and demonstrate that this is a copy (duplicate) of the Mother of God face in the apse mosaic of Santa Maria Assunta, Torcello, dated back to the 12th century. Their arguments are both of historic, technical and technological character. Basing on recent discoveries of late 19th century mosaic fakes destined to the international antiquity market, as well as on little known facts about replica and copies performed on Byzantine models, they advance the hypothesis that the Bologna mosaic in its actual form cannot be earlier than the 1860-ies and is most probably work of the mosaic master Enrico Podio, active in the second half of the 19th century between Rome and Venice.